The present invention relates to eyewear, and more particularly, to eyewear, such as eyeglasses having lenses with translucent regions used to reduce glare and/or increase visual acuity.
In recent years, various eyewear designs have been proposed to reduce glare and/or improve visual acuity, such as for use when viewing visual display terminals (VDTs) or participating in athletic activities. One particular eyewear design includes the use of upper and/or lower translucent bands or regions to reduce the amount of glare resulting from, for example, veiling illumination or ground glare. With respect to such an eyewear design, selected patents as discussed herein below are of interest, and are incorporated herein by reference.
U.S. Pat. No. 4,542,964 to Gislon et al. discloses an eyewear for reducing asthenopia developed by operators of visual display terminals (VDTs). The eyewear includes a frame removably positioned before the eyes which supports a transparent or clear optical region having an area extent for intercepting lines of sight only substantially below the mid-pupillary location of the eye. A translucent region extending upward from this latter mid-pupillary location advantageously blocks the eye""s superior field of view so as to reduce the amount of veiling illumination, such as from overhead and/or window lighting. Importantly, the translucent region is formed as having light diffusing characteristics, but of sufficient diffuse luminance to avoid the wearer experiencing a so-called xe2x80x9cblinderxe2x80x9d effect. See also, U.S. Pat. No. 4,470,673, which discloses similar eyewear.
U.S. Pat. No. 5,432,568 to Betz discloses an eyewear which reduces glare-related vision problems for target shooters, hunters, archers, and the like. The eyewear includes a transparent region provided within the frontal portion of, for example, eyeglasses, for intercepting lines of sight substantially above and below the standard line of sight located at about the mid-pupillary position of the eyes. To both reduce overhead glare, and glare reflected from the ground to a constant level of diffuse illumination, upper and lower translucent regions are used. Upper and lower translucent regions are provided to extend from the standard line of sight, and the upper and lower peripheries of the frontal portion of the eyeglasses, respectively, so as to intercept portions of the superior and inferior field of views.
Various methods may be used to fabricate the translucent region(s), such as by roughing or texturizing a portion of the front surface of the lens through sanding, sandblasting or chemical etching. Alternatively, the translucent optical region can be formed by coating, for example, a portion of the front surface of the lens with a material of sufficient translucency.
Unfortunately, not only are the prior art methods labor intensive, but also somewhat difficult to control, often resulting in poor quality and consistency. In applicant""s co-pending application identified herein above, a new process is disclosed for manufacturing eyewear lenses having at least one or more translucent regions, without the associated problems of the prior art. More specifically, to overcome the limitations of the prior art, applicant disclosed the use of an injection mold die having a selective portion thereof textured with a pattern or so-called xe2x80x9ctexture.xe2x80x9d This texture is replicated on the lens during molding, and employed to form the region of desired translucency on the finished lens.
In applicant""s co-pending application, an antireflective (AR) coating is also disclosed in combination with the translucent region, but applied to the clear portion of, for example, the front surface of the lens because of the discovered increased transmissivity if applied to the textured translucent region(s). That is, coating the textured translucent region(s) with an AR optical thin film would limit the translucent region""s ability to reduce overhead glare as well as ground glare because of its reduced ability to block glare.
Selectively coating the front surface of the lens, however, unfortunately increases the manufacturing cost. Accordingly, it is desirable in the art to provide for a more cost effective method for AR coating such lenses.
The present invention is addressed to solving, among others, the problem of AR coating lenses having at least one or more textured translucent regions, without altering the effectiveness of the translucent regions to reduce glare. A part of the uniqueness of the present invention is that the AR coating is applied on the surface that opposes the translucent region. Normally, the AR coating is applied on the clear region of the lens and only up to the lower border of the translucent region because of the increased transmissivity if applied to the translucent region. However, part of this invention is the discovery that AR coating the lens on the surface opposing the translucent regions does not limit its ability to block glare inasmuch as the coating does not alter the surface contour of the translucent region.
Preferably, the lens is tinted using, for example, conventional dying to further improve visual acuity. For example, the lens may be tinted with a color from the mid-spectral range of the visible spectrum, such as yellow and/or amber, where the spectral sensitivity of the eye is about at its peak. Of course, the lens may be fabricated for general use as sunglasses so as to reduce reflected glare.
Also, various optical coatings can also be applied on the surface that opposes the translucent region to imbue the lens with various desired optical transmission properties. For example, by suitable combinations of thin films of different indices and thickness, a tremendous number of transmission effects can be created from the resulting interference coating. Among the types of interference coatings which can be created are long or short wavelength transmission filters, band pass filters, or narrow bandpass filters. Other optical coatings may be applied to the opposing surface, such as an ultraviolet (UV), or polarization coatings.
Furthermore, it is contemplated that the lens may be also provided with a relatively low plus optical power, selected below about one diopter, about from 0.25 to 0.75 diopters. This correction enables the user to focus on near objects, without needing accommodation otherwise required if the clear region were plano in nature, thereby reducing or eliminating blurring that would occur at both distance and near viewing as a result of long periods of viewing.